全二维气相色谱技术及其进展

 许多分析问题的解决需要得到比一维色谱技术能提供的更高的分辨率。分离能力可通过使用多种分离技术或机理的组合来增强。此时 ,样品被分散在不同的时间维 ,最终的分辨率强烈地依赖于这些维间分离特性的差异。当它们之间没有关联 ,也即相互间正交时 ,系统可获得最高的分辨率。全二维气相色谱 (GC×GC)提供了一个真正的正交分离系统。它把分离机理不同而又互相独立的两支色谱柱以串联方式结合组成二维气相色谱。在这两支色谱柱之间装有的一个调制器起捕集再传送的作用。全二维色谱的峰容量为组成它的两支色谱柱各自峰容量的乘积。     

全二维气相色谱在石油地质样品分析中的应用进展

对石油地质样品的化学组成进行全面准确的剖析,可以获得丰富的地球化学信息,为油气勘探工作提供科学依据。然而,该类样品除了组成复杂之外,还易受到各种物理（如蒸发、乳化、扩散、溶解和吸附）、化学（如光降解）和生物（如微生物降解）过程的影响。这些特点给样品的分析研究工作带来了极大的困难,传统的一维气相色谱/质谱技术很难对其进行理想的分离。全二维气相色谱（GC×GC）作为新发展起来的一种分离技术,在复杂样品分析方面具有独特的优势,虽然在石油地质样品分析中的应用相对较晚,但也日益受到关注。本文主要综述了近5年来GC×GC在石油地质方面国内外的研究进展以及存在的主要问题,并对今后的研究进行了展望。     

全二维气相色谱在食品风味化学成分分析中的应用

食品风味是评价食品品质特征的重要指标。食品风味物质分析通常采用一维气相色谱或气相色谱-质谱联用法,但由于某些食品风味成分组成和基质复杂,无法用一维气相色谱将其完全分离。全二维气相色谱将分离机理不同而又相互独立的两根色谱柱以正交方式组合,显著提升了色谱分离能力和分析速度,可满足食品中风味化学成分的二次分离。该文综述了全二维气相色谱技术在未经二次加工的食用农产品(如水果、蔬菜和肉类)和经过二次加工的食品(如乳制品、饮品和调味品)中风味化学成分分析中的应用,展现了全二维气相色谱技术的特点,并为食品风味的解析提供参考。     

全二维气相色谱分析持久性有机污染物的应用进展

持久性有机污染物（POPs）组分复杂,在自然界中超痕量存在,其分离分析十分困难。全二维气相色谱（GC×GC）作为一种新型色谱技术,与传统的一维气相色谱相比,具有峰容量大、分辨率和灵敏度高等优势,越来越广泛地应用于环境有机污染物的分析。该文综述了近十年来全二维气相色谱在持久性有机污染物分析中的应用进展,主要包括全二维气相色谱在解决一些复杂POPs定性定量分析难题方面的应用,如二恶英、毒杀芬和短链氯化石蜡等;概述了全二维气相色谱对多种POPs同时定性定量分析的应用进展;讨论了全二维气相色谱在非目标有机污染物筛查分析中的应用,并对发展趋势及相关应用前景进行了总结展望。     

全二维气相色谱/飞行时间质谱法在莪术挥发油组成分析中的应用

通过优化GC×GC的柱系统、温度程序和调制参数等色谱条件,建立了分析中药莪术挥发油组成的全二维气相色谱/飞行时间质谱(GC×GC/TOFMS)方法,实现了莪术挥发油的单个组分与族组分分析.采用所建立的GC×GC/TOFMS方法,鉴定出匹配度大于800的组分有249种,其中单萜18种,单萜含氧衍生物34种,倍半萜35种,倍半萜含氧衍生物37种,有69种组分的体积分数大于0.02%.     

国内石化分析中的气相色谱技术进展

气相色谱(GC)技术在石化分析领域的应用是较为普及的,随着气相色谱技术本身的不断成熟,其在石化分析中的应用也日益普遍。以标准化专用色谱柱和多维色谱切换技术为基础,针对行业特定应用需求开发各种专用色谱分析系统和应用包,是近年来石化分析领域色谱技术应用的一个显著特点。这是专业化分工与商品化服务结合后给色谱技术工业化应用带来的新气象,可最大限度地降低对操作人员的技术要求、促进分析系统开发的专业分工。与这种趋势相应,国内石化行业的GC应用工作也有同样的特点。总体来看,专用系统的硬件平台以国外主要仪器生产厂的产…     

全二维气相色谱质谱联用检验柴油

采用全二维气相色谱质谱联用技术对柴油进行了分离定性,并对比分析了在不同程序升温速率、调制解调周期、色谱柱极性等条件下的分离情况,进而对实验条件进行了优化。实验发现在同一色谱柱条件下,改变调制解调周期对一维方向上分离情况影响不大,对二维方向上分离情况影响较为明显;不同极性色谱柱对柴油分离情况存在明显差异。并对柴油的组成成分进行了分析,并测算了其主要成分的相对比例关系,为今后不同型号、产地柴油的区分打下基础。     

气相色谱-串联质谱技术在环境监测中的应用进展

气相色谱–串联质谱(GC–MS/MS)因其强抗干扰能力和高灵敏度的特性,在环境监测领域得到广泛应用。综述了近年来GC–MS/MS技术在环境监测中关于空气、水、土壤及沉积物中污染物检测工作中的应用,并对该方法的性能进行了评价;根据环境监测的特点和需求,对GC–MS/MS技术在环境检测中的应用进行了展望。     

气相色谱-质谱法在人体气味分析中的应用进展

气相色谱-质谱法（GC-MS）是目前分析人体气味的主要技术手段，其不但可以分析人体气味的组成成分，还可以比较不同个体气味之间的差异。该文首先介绍了人体气味的提取和样品前处理的手段，随后对GC-MS在人体气味的采集及储存、成分分析及差异性研究、用于个体识别和健康表征等方面进行了综述，最后对GC-MS在人体气味分析中的发展趋势进行了展望。     

全二维气相色谱的原理、方法及应用概述

全二维气相色谱(GC×GC)是近几年来发展起来的一个新技术,与传统的多维色谱不同,它提供了一种真正的正交分离系统,其峰容量约等于两根柱各自峰容量的乘积,非常适合于复杂样品的分析。本文主要对GC×GC的原理、仪器、分析方法及其应用进行了评述,并展望了其未来发展趋势。     

Recent developments in the application of comprehensive two-dimensional gas chromatography

The literature on comprehensive two-dimensional gas chromatography (GC x GC) is reviewed, with emphasis on application-oriented studies published in the period 2004-2006. The various strategies that can be used in such studies, the state-of-the-art analytical performance and the high potential of GC x GC combined with time-of-flight mass spectrometric detection are highlighted.     

气相色谱近年的发展

简要阐述了近几年气相色谱(GC)的发展和特点。GC是一个成熟的技术,广泛地应用于各个领域,近几年GC的发展除了继续研究新的固定相和高性能的毛细管色谱柱之外,主要在全二维气相色谱(GC×GC)、快速GC、便携式GC仪和微型GC仪几个方面。近几年新研究的GC固定相主要集中在常温离子液体和各种环糊精的衍生物。现在GC研究者趋向于使用商品化的GC毛细管柱,而商品化的GC毛细管柱应用最多的是以含5%苯基的聚甲基硅氧烷为固定相的色谱柱。GC×GC发展迅猛,特别是关于调制器的研究,已开发出十多种调制模式,并广泛地应用于各个领域。为了适应大量样品的分析和现场分析,研究和开发了多种快速GC方法和仪器以及便携式GC仪。为了仪器的小型化和专属性检测,μGC仪的研究也稳步地发展起来。     

Application of comprehensive two-dimensional gas chromatography to sterols analysis

The applicability of comprehensive two-dimensional gas chromatography (GCxGC) for sterol analysis was investigated by separation and identification of endogenous sterols in standards, and spiked in human urine. The modulation temperature was optimized to achieve the best separation and signal enhancement. The separation pattern of trimethylsilyl (TMS) derivatives of sterols was compared on two complementary column sets. Whilst the BPX5/BPX50 column set offers better overall separation, BPX50/BPX5 provides better peak shape and sensitivity. Comparison of the identification power of GCxGC-TOFMS against both the NIST05 MS library and a laboratory created (in-house) TOFMS library was carried out on a free sterols extract of urine, derivatised and spiked at the World Anti-Doping Agency (WADA) limit of 2 ng mL(-1). The average match quality for 19 analysed sterols on the BPX50/BPX5 column set was 950/1000 when searched against the in-house library; only four were identified against the NIST05 library, at a match threshold of 800. The match quality of GCxGC-TOFMS spectra was superior to that for analysis using 1D GC-TOFMS for sterols spiked in urine at 10 ng mL(-1). An r(2)>0.997 was obtained for the concentration range between 0.25 ng mL(-1) and 10 ng mL(-1) for three selected sterols. The lowest limit of detection (LOD) was obtained for estrone (0.1 ng mL(-1)) and the highest LOD was for 5alpha-androstan-3alpha,11beta-diol-17-one, epitestosterone and cholesteryl butyrate (1 ng mL(-1)), using a match threshold of at least 800 and signal-to-noise ratio of at least 10. TOFMS coupled to GCxGC enabled satisfactory identification of sterols in urine at their LOD. A minimum acceptable match (MAM) criterion for urinary sterols using 2D retention times and TOF mass spectra is introduced. This study shows that GCxGC-TOFMS yields high specificity for steroids derived from urine, with detection limits appropriate for use in doping control.     

Flow-switching device for comprehensive two-dimensional gas chromatography

A simple flow-switching device has been developed as a differential flow modulator for comprehensive two-dimensional gas chromatography (GC x GC). The device is assembled from tubing, four tee unions, and a solenoid valve. The solenoid valve is located outside the oven of the gas chromatograph and is not in the sample path. The modulation technique has no inherent temperature restrictions and passes 100% of the primary column effluent to the secondary column(s). Secondary peaks are produced with widths at half maximum less than 100 ms when operating in GC x 2GC mode with a 2.0 s modulation period. The efficacy of this approach is demonstrated through the analysis of a standard mixture of volatile organic compounds (VOCs) and diesel fuel.     

Comparative visualization for comprehensive two-dimensional gas chromatography

This paper investigates methods for comparing datasets produced by comprehensive two-dimensional gas chromatography (GC x GC). Chemical comparisons are useful for process monitoring, sample classification or identification, correlative determinations, and other important tasks. GC x GC is a powerful new technology for chemical analysis, but methods for comparative visualization must address challenges posed by GC x GC data: inconsistency and complexity. The approach extends conventional techniques for image comparison by utilizing specific characteristics of GC x GC data and developing new methods for comparative visualization and analysis. The paper describes techniques that register (or align) GC x GC datasets to remove retention-time variations; normalize intensities to remove sample amount variations; compute differences in local regions to remove slight misregistrations and differences in peak shapes; employ color (hue), intensity, and saturation to simultaneously visualize differences and values; and use tools for masking, three-dimensional visualization, and tabular presentation with controls for graphical highlights to significantly improve comparative analysis of GC x GC datasets. Experimental results indicate that the comparative methods preserve chemical information and support qualitative and quantitative analyses.     

Detector technologies for comprehensive two-dimensional gas chromatography

The detector is an integral and important part of any chromatographic system. The chromatographic peak profiles (i.e. peak separation) should, ideally, be unaffected by the detector--it should only provide the sensing capacity required at the end of a column separation process. The relatively new technique of comprehensive 2-D GC (GC x GC) extends the performance of GC manyfold, but comes at a price--existing GC systems may not be adequately designed with the requirements of GC x GC in mind. This is primarily the need for precise measurement of very fast peaks entering the detector (e.g. as fast as 50 ms basewidth in some instances). The capacity of the detector to closely track a rapidly changing chromatographic peak profile depends on a number of factors, such as design of flow paths and make-up gas introduction, type of detector response mechanism, and the chemistry of the response. These factors are discussed here as a means to appreciate the technical demands of detection in GC x GC. The MS detector will not be included in this review.     

Amino acid analysis by using comprehensive two-dimensional gas chromatography

The separation characteristics of alkylchloroformate-derivatised amino acids (AAs) by using comprehensive two-dimensional gas chromatography (GC×GC) is reported. The use of a low-polarity/polar column set did not provide as good a separation performance as that achieved with a polar/non-polar column set, where the latter appeared to provide less correlation over the separation space. The degree of component correlation in each column set was estimated by using the correlation coefficient (r²; for ¹t_R and ²t_R data) with the low-polarity/polar and polar/low-polarity sets returning correlation coefficients of 0.86, and 0.00 respectively, under the respective conditions employed for the experiments. The 1.5-m non-polar ²D column (0.1-mm ID; 0.1-m film thickness) gave peak halfwidths of the order of 50–80 ms. Linearity of detection was good, over a three order of magnitude concentration range, with typical lower detection limit of ca. 0.01 mg L^–1, compared with 0.5 mg L^–1 for normal GC operation with splitless injection. The method was demonstrated for analysis of AAs in a range of food and beverage products, including wine, beer and honey. The major AA in these samples was proline. The Heineken beer sample had a relatively more complex and more abundant AA content compared with the other beer sample. The wine and honey samples also gave a range of AA compounds. Repetition of the sample preparation/analysis procedure for the honey sample gave acceptable reproducibility for individual AAs.